.30 carbine chambering problem not resolved

condor

as zeke mentions...something to try is trim cases to 1.280"
it may not sound like it should make that big of a difference, but its possible

CMP put out a paper about the M1-30 Carbine
this is from page 2 - first 2 paragraphs


MOST IMPORTANT: The .30 Caliber Carbine case has a maximum length of 1.290”. The fired and reloaded cases should be trimmed to minimum every reloading. Reloading die makers usually specify a longish "trim to" length on the order of 1.285”. The minimum length for Carbine cases is 1.280” and has been observed to be more satisfactory. This 1.280" is the normal factory length of new ammunition.

This length of 1.280” helps prevent failure to lock with the bolt forward but not rotated and subsequent out of battery firing. Too long of cases wedge the bolt forward, but do not allow easy rotation to full lock up. Too long of cases are the main cause of most problems. Carbine cases stretch at seeming random. Trim every reloading. Some cases will be unmarked by the trimmer cutter, others will be partially trimmed on one side, and others will be fully engaged with the trimmer cutter.

I uploaded the paper to your other thread
https://thefiringline.com/forums/showthread.php?t=583565

another thought is to pull one of your factory new rounds and compare measurements with your fired and resized cases

I hope you find an answer
its a fun gun to shoot
 
I have four suggestions/comments:

First, ditch the carbide die and just use the plain steel die... in my experience, the carbide die squeezes the neck area of the case way more than necessary for proper tension of the bullet.

Second, after trimming, DEFINITELY chamfer the inside of the case mouth and de-burr the outside... but do not cut the case mouth to a knife edge. If you do not, you will have issues with either the brass shedding into your chamber, or you will have the inside brass edges cutting into/shaving copper from the bullet jackets.

Third, trim all cases to 1.283" - 1.285" and that should be fine, unless you have a very unusual chamber. Maybe get headspace gauges and have your chamber cast to see if it is in spec.

Last, bell case mouths slightly... just enough to get bullet started and taper crimp just enough to get the mouth back to proper dimensions, and no more.

Unless there is something really wrong with your chamber (unlikely, since commercial ammo seems to function fine), you should be able to load your own successfully by sticking to the same dimensions. I have found that factory stuff is generally shorter than it needs to be.

Good luck!
 
Zeke, Billglass, Driftwood and others
Intending to trim some cases earlier today, another thing didn't go right. While I have the collet for the Forster trimmer, it turns out that the 30 pilot, good for '06 and other 30 caliber cases, would not work with the carbine cases after sizing. The diameter of the mouths of the carbine after sizing are under size and no way could the pilot could be used since it will not enter the case mouths at all. Regardless of which sizing die was tried, all five case brands had under sized mouths. So it was back to the Midway catalog for another 30 pilot which will require some size reduction. A 29 pilot would probably work but is not available and a 28 pilot is too small.

The Speer manual along with the Lyman both give trim to length as 1.285. Practically all my once fired cases after sizing are in the 1.290+ range. The pull down LC cases, unfired, are all quite consistent at around 1.285 and 1.286. And they may expand .001 after sizing (done just to see if there was any elongation). The above pilot order was the third order this week, on items that shipping and NRA roundup fees were more than the cost of the items. However I did include some Starline carbine brass with this order. Determined to get this thing operating properly.

Since I use the Dillon 550, case flaring is done with the powder measure system and the flare then removed during bullet seating. As far as chamfering goes, the closest I come to that is just deburring the inside of the case mouths (and the outside as needed of course). I seem to get the impression that some overdo the chamfering and end up with the knife edge.

There is certainly disagreement between which is better, the steel or the carbide sizing die. As pointed out several times I use both in tandem and probably the only one to ever do that. The steel die sizes the base better while the carbide die does a better job on the case body. Used together seems to be a perfect combination.

Note that the carbide die is not responsible for excessively squeezing down the case mouths since the same thing happens when just sizing with the steel die. I suppose a larger diameter expander button would be in order if available.
 
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I guess its not really proper, but after resizing, I expand my cases enough to get the trimmer pilot in the case mouth
It hasn't caused any issues
 
Hmmmmmm. A "maybe" observation.( AHHH! Billglas beat me to it!)

A 30-06 and a 30 carbine use the same diameter bullet (308)
The 30-06 expander ball in conventional dies gives sufficient neck tension to work in a Garand or hold up to recoil without bullets pulling.
I'm suggesting your 30-06 reloading dies produce adequate neck tension for a 30-06,so the same diameter should be adequate for 30 carbine.

If your trimmer pilot will fit your 30-06, think of your pilot,in this case,performing the function of a gage.

If your trimmer pilot is a "go" in a 30-06,and it is a "no go" in the carbine,it tells me your carbine brass is being sized to significantly more neck tension than your 30-06 is.

SO... Manual press,three die,,we size,then decap,expand,and bell with the next die.The expander plug is part of bell and decap. Then prime,charge,seat.crimp.

What is the sequence with your Dillon? Universal decap, size, prime,then,all with the powder station,expand,bell,and charge???

I guess I'm narrowing in on the diameter of your charge/expand/bell mandrel,or whether somehow an expander ball op has been skipped,or whether a custom hone to size job needs to be done on your sizer die.Or maybe the madrel that bells and the powder passes through is worn or undersize. Dillon gives excellent support.You might talk to them.Know the diameter of that part before you call.Maybe you just need to use a 30cal expander before you try to trim. I'm not sure I have the exact answer,but I may have found the right question.

If you CAN slip your 30-06 sized brass on your trimmer pilot,and you CANNOT slipyour 30 carbine on your trimmer pilot...we may be cutting copper rings with excess neck tension
 
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They're getting to it. My RCBS carbide .30 carbine die sizes the brass down past original dimensions. The die set came with an expander plug die, which re expands the brass to accept 30 caliber bullet, while creating a "stepped" case mouth instead of just a flare.

Likely you are forcing bullets into an undersized case, in addition to using cases beyond the max case length. The rings of copper might be caused by the ring being shaved off while seating the bullet, or the cases too long/chamber throat interaction.
 
HiBC and Zeke
Note that Billglass in post 24 reports the same problem with his 30 pilot not fitting in his sized cases but that he expands the case necks somehow to make a fit. And Zeke needs an expander die to sufficiently expand the case mouths for the pilot. But the 30 pilots work properly in everyone's '06 cases. Strange.

When I receive a new 30 pilot will reduce the diameter to fit. I've had to do that with another pilot and is not a problem.

Loading sequence with the Dillon 550 is as follows. With my questionable two sizing die setup, the steel die is in station 1 for depriming and better sizing the base of the cases. The carbide die in station 2 with decapping stem removed does some additional sizing on the case body. Powder charging and flaring with the powder measure system is done at station 3 and bullet seating and taper crimping done at station 4.

Of course trimming will have to be included following the two die sizing operation before going on to powder charging and flaring.

Bullet seating is done with normal pressure and no shearing of the bullets. But the 30 pilot is the problem with trimming right now.
 
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Compare the dia of the neck expanding feature on your Dillon setup to the expander plug on your 30-06 die.(Your 30-06 die sizes the neck down undersize,then draws the expander plug through to size the ID up a bit)

I understand the expediency of reducing the diameter of a trimmer pilot. That will accomplish letting you trim and chamfer after sizing. All good!!

Now,what I wonder,after you get them trimmed,will the ID of the 30 carbine case get expanded up to the same ID as 30-06 sized brass by the feature on your powder charger that also flares.
Or,to ask another way,once a 30 carbine case is charged with powder,is the ID of the case neck pretty close to the ID of a resized 30-06 brass?If you have good calipers you should be able to make a comparative measurement.I'd hope they were within .001 or so.
 
Yes, made a few measurements that explains what is going on but not why. Outside neck diameter of a sized LC carbine case is .327 and inside diameter is .297. With sized Fed '06 cases, outside diameter is .331 and inside diameter is .304. Case wall thickness at the neck is .013 for both. Measurements should be valid since 30 match Sierras always come out exact at .308. The '06 rounds are loaded on a single stage press with a Herters sizing die rather than with the Dillon.
 
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Another case sizing glitch:
While waiting for the new 30 pilot to arrive, I was successful in creating a 30 carbine pilot from a Lyman outside case neck turning mandrel that wasn't serving any purpose. Reducing the diameter to about .299 resulted in an excellent fit to most of the sized case mouths. So now I'm really set to do some sizing--right? Well not quite right. Inserting a case over the newly created pilot and pushing the cutter shaft inward as far as it would go, the case head lacked a half inch or more to enter the collet. The trimmer is the original Forster. However it was easy enough to hold the case body by hand to do the sizing. By that method I sized ten to 1.286 or 1.287 and loaded those. Wouldn't want to size 100 that way.

Have emailed Forster to see if they have a longer cutter shaft or some kind of adaptor for the original tool in order to properly size the 30 carbine cases.
 
Ok. IMO,progress

Your 30-06 shows a neck id of .304. That's .004 interference for neck tension.
Plenty.Would work in a Garand or a 300 RUM.

Your little Carbine brass shows .297 ID,or .011 interference for neck tension. Nearly three times as much. Stuffing a bullet into .011 interference certainly might shave a copper ring of some sort.
There are at least two ways to fix this.One might be honing nearly .007 out of the carbide sizing die.Maybe .0065. That should put the ID right about .3035.

Since the Carbine brass is tapered,no sense sizing the rest of the case body down .007 more than necessary. Forster used to offer some die honing services.You might check.

Or,Dillons" charge through the flaring tool" idea is fine,but it seems the expander function has been lost. I'd think Dillon has that figured out better than I can.Talk with them.Maybe they have a larger dia mandrel you can put in your charging station
Anyway,solution,I'm not sure whats best for you,but we may have ID'd the problem.
I wonder if Redding makes some bushing die where neck tension can be controlled with bushings. Probably expensive!
 
I suppose the slight flare prevents any shaving of the bullet during seating. Without the flare there no doubt would be shaving with .011 tension. The .297 ID is the measurement from sized Armscor cases. I just checked the ID of sized Winchester cases that turned out to be .031 or .032, still plenty of tension at around .006 or .007. The Herter's '06 sizing die probably seems odd but I use it mostly since it has a smaller diameter expander plug than a Bonanza and an RCBS, thereby providing more tension than the other two without reducing the diameter of their expander plugs. The .004 tension seems sufficient for the Garand. This is verified by an occasion or two during chambering a round that misfeeds and strikes the breech face without pushing the bullet inward. So right now I'm playing around with case sizing the carbine cases to 1.286 or 1.287. Most brands of fired and sized brass are up around 1.294 or more.
 
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Finally, a break through with a couple different bullets.

One is FMJ pull downs from military rounds that are .207 in diameter. Firing 10, there was no trace of copper whatever left in the chamber and all fed perfectly. Obviously, I would think, the military FMJ material is harder than the Sierra bullet FMJs. I did trim the cases to around 1.286 which may have helped things along. I'll certainly be doing some more business with patsreloading.com.

Ten rounds were then fired using the second bullet, a cast sized to .209. These are Hunters Supply brand and obtained through Midway. These 10 rounds all chambered and fired perfectly and the cases had also trimmed.

Next a few rounds were tried that were loaded with the Sierra FMJ bullets, and again the copper rings developed after firing two or three and the chamber then needing removal of the copper rings.

The above of course was with the Inland carbine and unfortunately the older carbine is showing the same signs of hanging up with the Sierra FMJ bullets. I have over 500 of the Sierra FMJs sitting in limbo. What now to do with them? Also have a few of my own pull-downs to attend to.
 
If you know anyone with a bore camera, might want to check out the chamber throating. Bought a cheaper Lyman Borecam, and found a couple of surprises.

Am guessing you meant .307 dia? Not all bullets have the full dia at the same length. yet another possible factor.
 
Yes, pull down bullets should read .307 and cast lead bullets .309. Ten shot group with the .307s was about the best yet. Cast bullets also very good. But not really into accuracy up to this point since main consideration has been trying to get the thing to digest the reloads properly. Didn't want to be restricted to factory rounds only.
 
I have over 500 of the Sierra FMJs sitting in limbo. What now to do with them?
Click to expand...

Either use them or sell them and recover your money. I know my Inland would have no problem digesting them.
 
Shr970
Is your Inland one of the new ones and what ammunition are you using? Any problems with reloads or anything else? Yes I'll probably take the five unopened boxes into my LGS and try to trade for one box of something else or a can of powder or primers. My next order of business is to get an email off to Pat's Reloading for a few hundred of the military pull downs.

I would certainly prefer to use the Sierras with the older carbine but they are also hanging up in that one.
 
My inland was from 1944. It isn't very pickey about diet. Old soldiers are used to eating the garbage they are fed.
 
30 carbine bullets for sale:

The final conclusion is that the copper rings formed in the chamber by certain bullets are responsible for obstructing the chamber and causing the failures to feed. This is happening with both the older carbine as well as with the new Inland. "Certain bullets" are the 110 gr x-treme plated and the Sierra 110 gr FMJs. The bullets that work are the 110 gr FMJ military pull downs, and the Hunters Supply 115 gr cast.

Note that the x-tremes and the Sierras both worked fine in a previous carbine. But not having that one any longer, I now have about 1200 30 carbine bullets that I can't really use. Would anyone be interested in buying these for half price? There is one unopened box of 500 x-tremes and about 200 additional from a previous box, and five unopened boxes of the Sierras, 100 per box.

The 500 box x-tremes are currently priced at $50, one half would be $25. The Sierras were $20 per box of 100, making half price for the five boxes $50. No charge for the 200 additional x-tremes. Include $10 for shipping for a total of $85. I would probably send by USPS priority mail.

If interested send me a personal message to arrange details. If there are no buyers, the only alternative would be for me to buy another carbine that the bullets will work with. ;)
 
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